I stumbled on this interesting project on YouTube. The modification is done to a $35 4K camera you can find on eBay. To that he adds a c-mount. Then this camera can take any c-mount lenses. There are scores of great inexpensive c-mount lenses out on eBay and elsewhere. You’ll also need a c-mount extension tube.
When you see the comparison shots between this cheap camera now with a c-mount lens and with a Panasonic G4, you’ll find it pretty remarkable considering the price difference.
When you remove the lens that comes with the $35 camera, you find it has a back infrared filter. So if you leave that off, you have an infrared camera that can do some fun work. Or you can add an infrared filter to the front of the lens and shoot normal video. If you add an external battery, this camera would be an ideal time lapse camera. Leaving any camera unattended for hours is risky. Better for a cheap disposable camera. Wouldn’t you love to play with the possibilities of a cheap c-mount camera?